Equilibrium Time Research Articles

Peach seed shell and Aspergillus oryzae as adsorbents for the uptake of acid violet 90 dye from wastewater

In this study, Aspergillus oryzae (A. Oryzae) biomass and waste peach seed shells (PPSS) were used to create alternative and effective adsorbents. Acid Violet 90 (AVD) dye was removed from wastewater using the as-prepared adsorbents. Different process variables like pH (2–11), contact period (0–180 min), and adsorbent mass (0.2–2.0 g/L) were examined. The solution pH had a synergistic effect on the improved removal of AVD and the optimal adsorption removal for the PPSS and the A. Oryzae adsorbent occurred at pH 2.0 and pH 5.0, respectively. The findings demonstrated that, in comparison to A. Oryzae, PPSS reported a greater AVD adsorption (mg/g). The equilibrium time for the adsorption process was attained within 180 min for both adsorbents. The adsorption kinetics modelling results showed a good fit with pseudo-second-order kinetics, for both adsorbents, with average R2 values of 0.999 (for PPSS) and 0.997 (for A. Oryzae). Similarly, the isotherm modelling results confirmed the good fitting of the Langmuir isotherm model for A. Oryzae (R2 = 0.999) and the Freundlich model for PPSS (R2 = 0.997). The maximum adsorption capacity (qmax) of 55.0 and 94.92 mg/g was recorded for A. Oryzae and PPSS, respectively. Mechanistic investigation of the present system suggests that both intraparticle diffusion and surface sorption mechanisms control the adsorption rate. As agro materials, both adsorbents are composed of mostly oxygen-based surface functional groups like the –OH, –C = O, -C-O-C, and multiple carbon-carbon bonds, all contributed to the synergistic mechanism interaction between the adsorbent and AVD dye in this study. This study, therefore, revealed that the PPSS and A. Oryzae may be very helpful for removing anionic dye from contaminated wastewater, indicating its potential for useful application in the removal of other major pollutants.

A longer period of epididymal sperm interaction with extender components during cryopreservation improves sperm quality, decreases the size of sperm distal cytoplasmic droplets, and changes the number of nanoparticles in the extender

While cryopreservation of cauda epididymal sperm (SpCau) allows the preservation of post-mortem bulls’ gametes, the process triggers sperm damage. Although improving post-thaw sperm quality, using egg yolk extenders (EY) raises biosafety concerns which forces the use of EY-free extenders (EYFE). Since EYFE are less efficient in preserving post-thaw sperm quality, a strategy for ejaculated sperm (SpEj) frozen with EYFE is to add an Equilibrium Time (ET) step period to the cryopreservation process. However, the ET effect on the quality of SpCau cryopreserved in EYFE remains unknown. Distinct from SpEJ, SpCau physiologically displays cytoplasmic droplets (CDs) in the flagellum that may benefit cell exchange during ET. We hypothesized that using ET in SpCau cryopreserved with EYFE impacts sperm morphofunctional features, CD area, and in vitro fertility ability. Extender nanoparticles were also assessed. Following collection from the cauda epididymis of six Nellore bulls by retrograde flow, SpCau were cryopreserved in EYFE BoviFree® (Minitube, Germany) using three ET protocols: ET0 (no-ET); ET2.5 (2.5 h-ET); and ET5 (5 h-ET). SpCau from ET2.5 and ET5 showed a higher (P ≤ 0.05) percentage of motility and integrity of plasma and acrosome membranes and a smaller (P ≤ 0.05) distal CD area. There are no differences in sperm abnormalities, oxidative stress, capacitation-like events, and in vitro fertility ability. However, a better sperm recovery was found after Percoll® selection for ET2.5 and ET5. Interestingly, the number of nanoparticles in the extender decreased in post-thawed samples. In conclusion, an ET of 2.5 or 5 h is required for an efficient SpCau cryopreservation using an EYFE.

Rapid and real-time analysis of multi-component dissolved gas in seawater by Raman spectroscopy combined with continuous gas−liquid separator

Rapid and sensitive detection of dissolved gases in seawater is quite essential for the investigation of the global carbon cycle. Large quantities of in situ optical detection techniques showed restricted measurement efficiency, owing to the single gas sensor without the identification ability of multiple gases. In this work, a novel gas−liquid Raman detection method of monitoring the multi-component dissolved gases was proposed based on a continuous gas−liquid separator under a large difference of partial pressure. The limit of detection (LOD) of the gas Raman spectrometer could arrive at about 14 μl·L−1 for N2 gas. Moreover, based on the continuous gas−liquid separation process, the detection time of the dissolved gases could be largely decreased to about 200 s compared with that of the traditional detection method (30 min). Effect of equilibrium time on gas−liquid separation process indicated that the extracted efficiency and decay time of these dissolved gases was CO2 >O2 >N2. In addition, the analysis of the relationship between equilibrium time and flow speed indicated that the decay time decreased with the increase of the flow speed. The validation and application of the developed system presented its great potential for studying the components and spatiotemporal distribution of dissolved gases in seawater.

Constructing the synergistic effects of chitosan and ionic liquid on SPEEK polymer for efficient adsorption of crystal violet dye

In the study, a novel chitosan biopolymer and 1-ethyl-3-methylimidazolium tetrafluoroborate ionic liquid (IL)-incorporated sulfonated poly (ether ether ketone) (SPEEK) composite (Ch-IL@SPEEK) was prepared for adsorption of cationic crystal violet (CV) dye. The proposed composite was well characterized by several techniques. CV adsorption performance was examined via batch studies by varying various variables involving adsorbent dosage, contact time pH and temperature. The isotherm results were demonstrated the adsorption characters of the processes were Langmuirian. The maximum adsorption capacity was determined as 77.66 mg g−1 for the composite which was significantly higher than SPEEK (qmax = 45.36 mg g−1). The determined equilibrium time of the operated system was 360 min and the kinetic model was assessed as Elovich. At low pHs the protonated surface groups repelled the positively charged CV and the adsorption rate increased with increasing pH. The process is spontaneous and favorable as it proceeds via endothermic interactions. Furthermore, even at the end of 5 successful adsorption cycles, 77.86 % CV removal was obtained. Remarkable efficiencies were also achieved in the removal performance of different organic pollutants. Based on the reported results, Ch-IL@SPEEK composite were exhibited as an impressive adsorbent material for adsorption processes.

Pore structure evolution and adsorption behaviors of porous poly (vinyl alcohol) hydrogel prepared using Na2SO4 and CaCO3 as porogens

AbstractIn this work, porous poly (vinyl alcohol) (PVA) hydrogels with different pore sizes were fabricated using inorganic non‐metallic porogens by an environmentally friendly method, providing a potential solution for the field of wastewater treatment. PVA hydrogels have gained much attention in the field of wastewater treatment due to their excellent adsorption performance and porous network structure. However, the employment of inorganic non‐metallic salts as porogens for PVA hydrogels has received limited attention so far. In this study, porous PVA hydrogels were prepared by freeze‐thawing and freeze‐drying with sodium sulfate (Na2SO4) and calcium carbonate (CaCO3) as porogens. PVA‐Na exhibited denser network structure with the concentration of Na2SO4 solution increased, and the tensile stress was enhanced by about 45 times. Meanwhile, the tensile stress of PVA‐Ca was improved significantly from 0.06 to 1.67 MPa, and the network structure became looser after adding CaCO3. Moreover, a comprehensive investigation was conducted on the adsorption performance of porous PVA hydrogel for Congo red (CR). Finally, five adsorption models were fitted to investigate the adsorption mechanism of porous PVA hydrogels, in which the maximum adsorption capacity of CR by PVA‐Na‐0.5 was predicted to be 215 mg/g by the Langmuir isothermal model fitting.Highlights The structure of PVA hydrogels was adjusted by Na2SO4 and CaCO3, respectively. The tensile stress of PVA‐Na with dense network structure increased 45 times. Compared to PVA‐FD, swelling equilibrium time of PVA‐Na reduced from 24 to 6 h. Equilibrium swelling rate of PVA‐Ca declined by half in comparison to PVA‐FD. Langmuir isothermal model predicted qmax of 215 mg/g for CR by PVA‐Na‐0.5.

Removal of the bemacid blue E-TL using granular activated carbon from abundant biomass: adsorption isotherm, thermodynamic and kinetic studies

In this work, we were interested in the adsorption of an acid dye, Bemacid Blue E-TL by granular activated carbon based on olive stones. To shed light on the adsorption process, batch experiments were performed to study the effect of operating parameters on the adsorption process such as equilibrium time, GAC dose, pH, initial dye concentration, and temperature. The experimental results showed that the adsorption of the dye Bemacid Blue E-TL by GAC based on olive stones depends on the equilibrium time at 8 hours, the pH is 2 of the solution and the dose is 5 g.L-1. To explain the adsorption equilibrium, the experimental values were examined by Langmuir, Freundlich, and Temkin models. The equilibrium is perfectly described by the Langmuir model whose correlation coefficient is higher than 0.99. The maximum retained quantity of the Bemacid Blue E-TL is 55.6 mg.g-1. Different kinetic models such as pseudo-first order, pseudo-second order, and the intraparticle diffusion equation were used to evaluate the adsorption kinetics. The results of the kinetic modeling showed that the pseudo-second order fitted the data well, with a high coefficient of determination (R2 > 0.99) and intra-particle diffusion is not the only rate-limiting step. The thermodynamic parameter values enthalpy (ΔH°), entropy (ΔS°), and energy change (ΔG°) show that the adsorption processes are endothermic and spontaneous. The various results obtained are promising and encouraging to consider a more comprehensive study with the objective of showing that the adsorbent chosen for this study is effective and could be used as a low-cost adsorbent for acid dye removal.

Study on Emulsification Effect of Crude Oil in Brine Emulsions by Automated Demulsibility Tester

The purpose of the surfactants used is to greatly reduce the interfacial tension between the crude oil and brine, thereby decreasing the capillary number. The resulting oil-in-water emulsions are often grouped according to the Winsor theory. Oil recovery aims to produce Winsor type-III emulsions because they have the lowest interfacial tension values and the most favorable flow properties. The sensitivity of oil–water–surfactant systems to environmental influences (e.g., mixing speed and equilibration time) increases close to the favorable environmental range (temperature, brine total salt concentration, pressure, etc.) of the Winsor III type, the middle microemulsion phase, which is favorable for crude oil recovery. The tests aimed to investigate the quality and quantity of emulsions prepared with surfactants used in enhanced oil recovery (EOR) using an automatic device to characterize and select surfactants for industrial petroleum applications. An essential method for surfactant selection is to study the emulsifying effect and phase behavior. Phase behavior tests and emulsifying effect tests were performed on surfactants and surfactant packages as a function of mixing parameters. The mixing speed and mixing time can influence the results of the phase behavior and emulsifying effect tests, although during the investigations, other parameters were unchanged.

Effects of dissolved organic matter from sludge pyrolysis biochar on the triclosan removal from contaminated soil

When sludge biochar (SC) prepared from sewage sludge was used to remove triclosan (TCS) from both aqueous solution and soil, the adsorption capacity increased with increasing pyrolysis temperature, while the degradation rate showed a different pattern, namely, SC-500 > SC-800 > SC-600 > SC-700. TCS degradation rate achieved nearly 100 % at 2 h with SC-500 used as a Fenton catalyst. Aromaticity of dissolved organic matter (DOM) was positively correlated with the degradation of TCS and adding homologous DOM solution shortened the equilibrium time of TCS degradation, while removing DOM from SC prolonged, compared to the original SC. The results of X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance spectrometer (EPR) characterization indicated that SC-500 performed a stronger catalytic degradation ability due to the relatively high Fe2+ content to produce more ∙OH and SC-derived DOM act as an electron shuttle to promote other reactive oxidative species generation through two free radical pathways in the activation of H2O2 by Fe2+, which in turn promoted the degradation of TCS.

Vitrification of feline ovarian tissue: Comparison of protocols based on equilibration time and temperature

Global contraction of biodiversity pushed most members of Felidae into threatened or endangered list except the domestic cat (Felis catus) thence preferred as the best model for conservation studies. One of the emerging conservation strategies is vitrification of ovarian tissue which is field-friendly but not yet standardized. Thus, our main goal was to establish a suitable vitrification protocol for feline ovarian tissue in field condition. Feline ovarian tissue fragments were punched with biopsy punch (1.5 mm diameter) and divided into 4 groups. Group 1 was fresh control (Fr), while the other three were exposed to 3 vitrification protocols (VIT_CT, VIT_RT1 and VIT_RT2). VIT_CT involved two step equilibrations in solutions containing dimethyl sulfoxide (DMSO) and ethylene glycol (EG) for 10 min each at 4 °C. VIT_RT1 involved three step equilibration in solutions containing DMSO, EG, polyvinylpyrrolidone and sucrose for 14 min in total at room temperature, while in VIT_RT2 all conditions remained the same as in VIT_RT1 except equilibration timing which was reduced by half. After vitrification and warming, fragments were morphologically evaluated and then cultured for six days. Subsequently, follicular morphology, cellular proliferation (expression of Ki-67, MCM-7) and apoptosis (expression of caspase-3) were evaluated, and data obtained were analysed using generalised linear mixed model and chi square tests. Proportions of intact follicles were higher in Fr (P = 0.0001) and VIT_RT2 (P = 0.0383) in comparison to the other protocols both post warming and after the six-day culture. Generally, most follicles remained at primordial state which was confirmed by the low expression of Ki-67, MCM-7 markers. In conclusion, VIT_RT2 protocol, which has lower equilibration time at room temperature has proven superior thus recommended for vitrification of feline ovarian tissue.

Nanocrystalline sodium mordenite as an efficient low-concentration CO2 adsorbent

Systematic control of the crystal size and morphology of zeolites to enhance their CO2 adsorption performance is of great importance from both environmental and economic perspectives. Here we report the seeded synthesis of sodium mordenite (Na-MOR) with a Si/Al ratio of 4.9 and an average crystal length and width of 70 and 40 nm, respectively, using γ-aminobutyric acid as a crystal growth inhibitor in the absence of any organic structure-directing agent (OSDA). This nanozeolite shows an unprecedented CO2 capacity of 1.58 mmol g−1 under dynamic direct air capture (DAC) conditions at 25 °C, which is approximately 40 % greater than the value (1.15 mmol g−1) of the best zeolite adsorbent (an unidentified OSDA-directed Na-MOR (Si/Al = 5.0) zeolite with Na+ enrichment in 8-ring side pockets), mainly due to its nanocrystalline nature. It has also been characterized by much faster CO2 adsorption kinetics (ca. 5 vs. 50 min equilibration time) compared to a commercial Na-MOR zeolite with Si/Al = 5.0. Our study paves the way for developing a more efficient zeolite-based DAC adsorbent.

Preparation and Characterization of Ferrihydrite: Application in Arsenic Removal from Aqueous Solutions

Arsenic pollution is a public health hazard in Burkina Faso due to its impact on human health and water resources. To mitigate this pollution, ferrihydrite material has been synthesized and characterized to be used as adsorbent for arsenic removal in aqueous solutions. This study aimed to contribute to improve of access to clean drinking water by removing arsenic from water using ferrihydrite. Arsenic species such as As(III) and As(V) were removed through batch adsorption. Experiments were carried out in batch mode using arsenic aqueous solutions. The characterization of ferrihydrite using Scanning Electron Microscopy (SEM) coupled with Energy Dispersive Spectroscopy (EDX), X-ray Diffraction (XRD), Infrared (IR), and Brunauer Emmett Teller (BET) showed that an amorphous and microporous 2-line ferrihydrite. The total specific surface area and pH at point of zero charge (pHpzc) were 184.518 m²/g and 9.41, respectively. The optimal adsorbent doses were 4 g/L for As (V) and 8 g/L for As (III). The optimum pH range for the adsorption of As (V) and As (III) was between 2 and 10, The maximum adsorption capacity was 15.07 mg/g for As(V) and 13.01 mg/g for As(III) with increasing concentration between 2 and 16 mg/L. Equilibrium time for As (V) and As (III) on ferrihydrite was found to be 720 min and 960 min, respectively. The adsorption of As(V) and As(III) was consistent with the Langmuir monolayer model on ferrihydrite. Arsenic adsorption was occurred according to spontaneous chemical reaction. Arsenic removal was occurred on a monolayer following the pseudo-second order kinetic.

Synthesis of a novel tertiary amine chloride type cationic covalent organic framework at room temperature for rapid removal of Cr(Ⅵ)

Persistent toxic heavy metal Cr(Ⅵ) oxyanions is increasingly damaging to the environment and human life safety. In this study, a novel tertiary amine chloride type cationic covalent organic framework with high yield (>95%) was synthesized using a one-step Schiff base reaction by room temperature standing two functional monomers. The adsorbent was characterized by SEM, EDS, FTIR, NMR, PXRD, BET, TGA and pHPZC. And a series of adsorption experiments were conducted to verify the removal effect for Cr(Ⅵ). It exhibited excellent adsorption performance and the adsorption equilibrium time was within 10 min, superior to most adsorbents. The adsorption conformed to the pseudo-second-order kinetics and the Langmuir adsorption isothermal models based on the values of R2 and RMSE in the corresponding four models. The impact of pH was significant, and the maximum adsorption capacity was 161.4 mg/g at a pH of 2. The adsorbent had good adsorption selectivity for Cr(Ⅵ) oxyanions in the presence of coexisting ions (Cl−, SO42−, NO3−, and PO43−), and good recyclability with only decrease of removal rate from 98.3% to 91.5% after five cycles. The mechanism for Cr(Ⅵ) adsorption was mainly attributed to ion exchange, and hydrogen bonding also played a subordinate role. In the Cr(Ⅵ)-MO binary system, the increase for Cr(VI) adsorption results from the new active sites in methyl orange. This work highlights the mild synthetic conditions, fast adsorption rate, and good adsorption of Cr(Ⅵ), which make it a promising prospect.

High performance adsorptive removal of emerging contaminant paracetamol using a sustainable biobased mesoporous activated carbon prepared from palm leaves waste

In this work, a novel bio-based carbon material was prepared via a facile pyrolysis method using chemically activated dead palm leaves as a sustainable and efficient carbon precursor. The as-prepared activated carbon with KOH activation (AC-KOH) was characterized by XRD, FTIR, SEM, EDS, and BET analysis. The AC-KOH was used for the adsorption of paracetamol (PCT) from aqueous solutions and the effect of experimental conditions such as contact time (0.08–30 hours), pH (2.96–12.1), initial drug concentration (1–50 mg L−1), adsorbent dosage (0.12–1.2 g L−1), and temperature (25–45 °C) was investigated. The system achieved equilibrium in 4 hours and PCT uptake was highly dependent on solution pH. A maximum removal efficiency was achieved at a pH of around 5.86. Kinetic model analysis indicated that the uptake follows the pseudo-second-order model (R2 = 0.989). The maximum monolayer capacity of the developed AC for PCT was found to be 87.87 mg g−1 at time of equilibrium (4 hours), solution pH of 5.86, adsorbent dose of 0.2 g L−1, concentration of 1–50 mg L−1 and temperature of 25 °C. The PCT uptake process was feasible, spontaneous (ΔG0 < 0), and endothermic (ΔH0 > 0) according to the thermodynamics evaluation. The mechanism of PCT adsorption primarily involved pore-filling, π-π interaction, and H-bonding. The adsorbent exhibited reasonable reusability towards PCT adsorption up to two regeneration cycles. The results of this work support that the dead palm leaves are efficient, cheap, and sustainable feedstock for producing activated carbon adsorbent to be used for an efficient removal of PCT from real wastewater samples.

ACTIVATED CARBON PREPARED FROM SOFTWOOD LIGNOCELLULOSIC BIOMASS – OPUNTIA FICUS INDICA CORDS TO REMOVE AN ANIONIC DYE

In this work, lignocellulosic biomass, namely, Opuntia ficus indica cords (OFIC), was selected as a renewable resource for the production of activated carbon. The preparation conditions of chemically activated carbon (AC) samples were the following: activation temperature – 600 °C, heating rate – 10 °C min-1, activation time – 60 min, and OFIC/H3PO4 impregnation ratio – 1/2. The properties of OFIC and activated carbon were determined by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), Boehm’s method, and pHzpc. AC showed heterogeneous surface and acidic characteristics with a pHZPC of 2.61. OFIC and AC were used as adsorbents to remove the anionic dye Red Bemacid (RB) from aqueous solutions. OFIC was used as a reference for comparison with the prepared AC. The results showed that the experimental data fitted very well with the pseudo-second-order nonlinear model of both adsorbents, with 120 min as equilibrium time and the nonlinear isotherm models of three parameters (Sips and Redlich-Peterson isotherms) were selected as the best fitting ones. The thermodynamic parameters indicated that the adsorption process was spontaneous and endothermic for the AC/RB dye system.

CHARMM-GUI Membrane Builder for Lipid Droplet Modeling and Simulation.

Lipid droplets (LDs) are organelles that are necessary for eukaryotic and prokaryotic metabolism and energy storage. They have a unique structure consisting of a spherical phospholipid monolayer encasing neutral lipids such as triacylglycerol (TAG). LDs have garnered increased interest for their implications in disease and for drug delivery applications. Consequently, there is an increased need for tools to study their structure, composition, and dynamics in biological contexts. In this work, we utilize CHARMM-GUI Membrane Builder to simulate and analyze LDs with and without a plant LD protein, oleosin. The results show that Membrane Builder can generate biologically relevant all-atom LD systems with relatively short equilibration times using a new TAG library having optimized headgroup parameters. TAG molecules originally inserted into a lipid bilayer aggregate in the membrane center, forming a TAG-only core flanked by two monolayers. The TAG-only core thickness stably grows with increasing TAG mole fraction. A 70 % TAG system has a core that is thick enough to house oleosin without its interactions with the distal leaflet or disruption of its secondary structure. We hope that Membrane Builder can aid in the future study of LD systems, including their structure and dynamics with and without proteins.

Near Equilibration Times in the Diffusion-Controlled Adsorption.

A model of the Frumkin isotherm following adsorption on the surface of the rotating disk is developed with the purpose to calculate the time that is needed for the establishment of the near equilibrium state between the amount of adsorbate and the bulk concentration of surfactant. The "near" is quantified as 99% of the proper equilibrium surface coverage. The near equilibration time depends on the bulk concentration and on the coefficient of molecular attraction in the adsorbed layer. In the vicinity of the inflection point of the isotherm, this time exhibits sharp spike. It is caused by the diminished flux that increases surface coverage very slowly but continues for a long time. Eventually, both the flux and the surface coverage increase with time drastically under the influence of the exponential part of the Frumkin isotherm.

Sulfur vacancy-rich bismuth sulfide nanowire derived from CAU-17 for radioactive iodine capture in complex environments: Performance and intrinsic mechanisms

Effective capture and immobilization of volatile radioiodine from the off-gas of post-treatment plants is crucial for nuclear safety and public health, considering its long half-life, high toxicity, and environmental mobility. Herein, sulfur vacancy-rich Vs-Bi2S3@C nanocomposites were systematically synthesized via a one-step solvothermal vulcanization of CAU-17 precursor. Batch adsorption experiments demonstrated that the as-synthesized materials exhibited superior iodine adsorption capacity (1505.8 mg g−1 at 200 °C), fast equilibrium time (60 min), and high chemisorption ratio (91.7%), which might benefit from the nanowire structure and abundant sulfur vacancies of Bi2S3. Furthermore, Vs-Bi2S3@C composites exhibited excellent iodine capture performance in complex environments (high temperatures, high humidity and radiation exposure). Mechanistic investigations revealed that the I2 capture by fabricated materials primarily involved the chemical adsorption between Bi2S3 and I2 to form BiI3, and the interaction of I2 with electrons provided by sulfur vacancies to form polyiodide anions (I3-). The post-adsorbed iodine samples were successfully immobilized into commercial glass fractions in a stable form (BixOyI), exhibiting a normalized iodine leaching rate of 3.81 × 10−5 g m−2 d−1. Overall, our work offers a novel strategy for the design of adsorbent materials tailed for efficient capture and immobilization of volatile radioiodine.

HiPSC-CM electrophysiology: impact of temporal changes and study parameters on experimental reproducibility.

Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are frequently used for preclinical cardiotoxicity testing and remain an important tool for confirming model-based predictions of drug effects in accordance with the comprehensive in vitro proarrhythmia assay (CiPA). Despite the considerable benefits hiPSC-CMs provide, concerns surrounding experimental reproducibility have emerged. We investigated the effects of temporal changes and experimental parameters on hiPSC-CM electrophysiology. iCell cardiomyocytes2 were cultured and biosignals were acquired using a microelectrode array (MEA) system (2-14 days). Continuous recordings revealed a 22.6% increase in the beating rate and 7.7% decrease in the field potential duration (FPD) during a 20-min equilibration period. Location-specific differences across a multiwell plate were also observed, with iCell cardiomyocytes2 in the outer rows beating 8.8 beats/min faster than the inner rows. Cardiac endpoints were also impacted by cell culture duration; from 2 to 14 days, the beating rate decreased (-12.7 beats/min), FPD lengthened (+257 ms), and spike amplitude increased (+3.3 mV). Cell culture duration (4-10 days) also impacted cardiomyocyte drug responsiveness (E-4031, nifedipine, isoproterenol). qRT-PCR results suggest that daily variations in cardiac metrics may be linked to the continued maturation of hiPSC-CMs in culture (2-30 days). Daily experiments were also repeated using a second cell line (Cor.4U). Collectively, our study highlights multiple sources of variability to consider and address when performing hiPSC-CM MEA studies. To improve reproducibility and data interpretation, MEA-based studies should establish a standardized protocol and report key experimental conditions (e.g., cell line, culture time, equilibration time, electrical stimulation settings, and raw data values).NEW & NOTEWORTHY We demonstrate that iCell cardiomyocytes2 electrophysiology measurements are impacted by deviations in experimental techniques including electrical stimulation protocols, equilibration time, well-to-well variability, and length of hiPSC-CM culture. Furthermore, our results indicate that hiPSC-CM drug responsiveness changes within the first 2 wk following defrost.

Preparation and properties of activated carbon-based Na3PO4 composites for low-temperature thermochemical heat storage

With the advantages of low heat storage temperature, high heat storage density, and a low price, Na3PO4 has been proposed as a thermochemical heat storage candidate material for use in solar low-temperature heat storage engineering applications. However, the application of pure Na3PO4 is limited due to its propensity for agglomeration. In this study, activated carbon-based Na3PO4 (R-AC@Na3PO4) composites with mass fractions of 30 %, 50 %, and 80 % were synthesized by melt impregnation method using activated carbon as the porous matrix. The morphology and structure of the composites were characterized, and their heat storage performances were investigated. The hydration experiments were carried out in a constant temperature and humidity chamber and dehydration experiments were carried out in thermogravimetric analysis and differential scanning calorimetry simultaneously. The results showed that at 30 °C, 60 % relative humidity, the hydration equilibrium time for the composites were only 30 %–40 % of the pure material. Meanwhile, at a mass fraction of 80 %, material's volumetric heat storage can reach 1793 J·cm−3 without agglomeration, and the performance was stable after 20 cyclic tests. This study provides a reference for the research and development of low-temperature thermochemical heat storage materials and offers more possibilities for R-AC@Na3PO4 composites in future engineering applications.

Using Phragmites australis plants as activated carbon to remove Mn(II), and Cu(II) ions from different aqueous solutions

This study investigates the use of agricultural byproducts of plants (Phragmites australis) as low-cost adsorbents for the removal of Cu2+ and Mn2+ from their aqueous solutions through the production of (AC). The results showed that the adsorption equilibrium time for both ions was 30 minutes. The results obtained showed that pH=5, pH=6 for Cu2+ and Mn2+ respectively were optimum to adsorption for these ions. The study showed that the weight (0.5 g) of the adsorbent was ideal to achieve the best adsorption and the ability of the adsorbents to adsorb metal ions was as follows: Cu(II) &gt; Mn(II).